Fluorinated olefins, as a class, have many and varied uses, including as chemical intermediates and monomers, refrigerants, blowing agents, propellants and solvents.
Several methods for preparing fluorinated olefins are known. For example, U.S. Pat. No. 5,679,875 discloses methods for manufacturing 1,1,1,2,3-pentafluoropropene and 1,1,1,2,3-pentafluoropropane; U.S. Pat. No. 6,031,141 discloses a catalytic process using chromium-containing catalysts for the dehydrofluorination of hydrofluorocarbons to fluoroolefins; U.S. Pat. No. 5,396,000 discloses a process for producing CF3CHFCH2F using vapor phase catalytic dehydrohalogenation to produce CF3CF═CHF and HF, followed by vapor phase catalytic hydrogenation of CF3CF═CHF in the presence of HF; U.S. Pat. No. 6,548,719 discloses a process for producing fluoroolefins by dehydrohalogenating a hydrofluorocarbon in the presence of a phase transfer catalyst; U.S. Publication No. 2006/0106263 discloses the production and purification of hydrofluoroolefins compounds; and WO98/33755 discloses catalytic process for the dehydrofluorination of hexafluoropropanes to pentafluoropropenes.
Applicants have also come to appreciate that 1,1,1,2,3-pentafluropropene (HFO-1225ye) and 1,1,1,2-tetrafluoropropene (HFO-1234yf) are each useful in various application, and in certain application, one of the compounds might be favored over the other. For example, HFO-1234yf is more preferred than HFO-1225ye for certain refrigerant and blowing agent applications.
Applicants have previously developed a process for producing HFO-1234yf which involves hydrogenating HFO-1225ye to produce 1,1,1,2,3-pentafluropropane (HFC-245eb) and then using the HFC-245eb as a reactant in a dehydrofluorination reaction to produce HFO-1234ye. Applicants have also previously developed a process for producing HFO-1225ye which involves first hydrogenating hexafluoropropylene (HFP) to produce 1,1,1,2,3,3-hexafluropropane (HFC-236ea) and then using the HFC-236ea as a reactant in a dehydrogenation reaction to produce HFO-1225ye. To commercially produce these two products according to these prior art processes, a manufacturing facility would require a minimum of four separate unit operations for each product, i.e., hydrogenation of the starting material, separation of the desired intermediate, dehydrofluorination of the intermediate to produce the desired product, followed by another separation to isolate the desired product. Applicants have come to appreciate that substantial economic investment would be required to develop such a commercial facility. As a result, it might become economically prohibitive to build a processing facility to produce each of these desirable fluorinated olefins according to the prior art processes.
In view of applicants' recognition of the above-noted problems and features of prior processes, applicants have developed improved processes that are capable of achieving substantial economic advantage in capital cost as well as substantial flexibility and advantage in the actual operation to maximize efficiency and production of a range of fluorinated olefins.